Powered spiral conveyors are useful in the mining of coal, and other material. For example as shown in U.S. Pat. No. 4,082,362 (the disclosure of which is hereby incorporated by reference herein), a number of spiral conveyor sections can be connected together to effect conveyance of mined material from a cutting site to the mine mouth. While such spiral conveyors are desirable, there is an inherent limitation in the distance that mined material can be transported thereby. If it is desirable to convey the mined material a long distance, e.g. about 1,000 feet, it is impractical to apply enough power to one end of the spiral conveyor section, e.g. at the mine mouth, to effect proper and speedy conveyance of mined material thereby all the way from the cutting site to the mine mouth.
In order to overcome the above mentioned problem, according to the present invention powered spiral conveyor sections are provided. Each conveyor section includes at least one spiral conveyor, and a power source, such as a 100 horsepower motor. The power source drives the spiral associated with that section. Various sections may be interconnected by in-line shaft portions extending therebetween, with support struts provided as necessary. Also, spiral conveyors can be mounted in gangs, for example two spiral conveyor sections may be mounted for a given section with a motor, gear train, and drive chain associated with each of the spiral conveyors. Typically there is at least 1/4-3/4 horsepower of the power means for driving each foot of spiral conveyor (if its diameter is about 32-36").
The spiral conveyors may be associated with a mining machine including a mining head, with the spiral conveyor means extending from the mining head toward the mine mouth. With power means disposed at periodic intervals along the conveyor means for providing power for rotating the shaft of the spiral, the conveyor may extend about 1,000 feet or more from the mining head to the mine mouth, and still be effectively powered.
According to a method of the present invention, mining of a mine having a mine mouth, using a mining head with a spiral conveyor having a spiral screw rotatable with a shaft about an axis of rotation, is provided. The method comprises the steps of: (a) Inserting the mining head into the mine through the mine mouth, and advancing the head into the mine mouth. (b) Continuously conveying mined material from the mine toward the mine mouth using the spiral conveyor. (c) Adding incremental lengths to the spiral conveyor screw as the distance from the mining head to the mouth increases. And, (d) periodically providing power assists for effecting powered rotation of the spiral conveyor about its axis of rotation along the length of the spiral conveyor in the mine as the incremental lengths are added. Preferably step (d) is practiced so that there is at least about one horsepower of power assist for each foot of spiral screw, and more preferably about two horsepower of power assist for each foot of spiral screw.
It is the primary object of the present invention to provide for the effective conveyance of mined material using a spiral conveyor, over long distances. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.